Zend_Config_Writer gives you the ability to write config
files out of Zend_Config objects. It works with an
adapter-less system and thus is very easy to use. By default
Zend_Config_Writer ships with four adapters, which are all
file-based. You instantiate a writer with specific options, which
can be filename and config. Then
you call the write() method of the writer and the config
file is created. You can also give $filename and
$config directly to the write() method.
Currently the following writers are shipped with
Zend_Config_Writer:
Zend_Config_Writer_ArrayZend_Config_Writer_IniZend_Config_Writer_JsonZend_Config_Writer_XmlZend_Config_Writer_Yaml
When modifying or creating a Zend_Config object, there are
some things to know. To create or modify a value, you simply say set
the parameter of the Zend_Config object via the parameter
accessor (->). To create a section in the root or to
create a branch, you just create a new array
("$config->branch = array();"). To define which section
extends another one, you call the setExtend() method
on the root Zend_Config object.
Example 120. Using Zend_Config_Writer
This example illustrates the basic use of
Zend_Config_Writer_Xml to create a new config file:
<?php
// Create the config object
$config = new Zend_Config(array(), true);
$config->production = array();
$config->staging = array();
$config->setExtend('staging', 'production');
$config->production->db = array();
$config->production->db->hostname = 'localhost';
$config->production->db->username = 'production';
$config->staging->db = array();
$config->staging->db->username = 'staging';
// Write the config file in one of the following ways:
// a)
$writer = new Zend_Config_Writer_Xml(array('config' => $config,
'filename' => 'config.xml'));
$writer->write();
// b)
$writer = new Zend_Config_Writer_Xml();
$writer->setConfig($config)
->setFilename('config.xml')
->write();
// c)
$writer = new Zend_Config_Writer_Xml();
$writer->write('config.xml', $config);
This will create an XML config file with the sections production and staging, where staging extends production.
Example 121. Modifying an Existing Config
This example demonstrates how to edit an existing config file.
<?php
// Load all sections from an existing config file, while skipping the extends.
$config = new Zend_Config_Ini('config.ini',
null,
array('skipExtends' => true,
'allowModifications' => true));
// Modify a value
$config->production->hostname = 'foobar';
// Write the config file
$writer = new Zend_Config_Writer_Ini(array('config' => $config,
'filename' => 'config.ini'));
$writer->write();
Loading a Config File
When loading an existing config file for modifications it is very important to load all sections and to skip the extends, so that no values are merged. This is done by giving the skipExtends as option to the constructor.
For all the File-Based writers (INI, JSON,
XML, YAML, and PHP Array)
internally the render() is used to build the configuration string.
This method can be used independently to access the string-representation of the
configuration data.